Glassy carbon electrode modified with hemin and new melamine compounds for H2O2 amperometric detection

Abstract

In an attempt to increase the stability and efficiency of hemin-modified electrodes, the present work reports the preparation of a new modified glassy carbon electrode obtained by immobilization of hemin (Hm) on the electrode surface together with a new N-substituted melamine (2,4,6-triamino-1,3,5-triazine) based G-2 dendrimer comprising paminophenol as peripheral unit (Den) or with one of its analogues, a melamine G-0 dimer (Dim). Basic structural features, able to determine intimate relationships between Hm and Dim (or Den) at room temperature in solid state, were evidenced with the use of vibrational analysis carried out by FT-IR. This method revealed contacts between Hm and Dim or Den respectively as H-bond interactions, proton-interchange, and π-π stacking interactions. The new modified electrodes were characterized by cyclic voltammetry and electrochemical impedance spectroscopy and tested for amperometric detection of H 2 O 2 . In this purpose, GC/Hm-Dim electrode exhibited better catalytic properties than GC/Hm-Den electrode, but lower stability.

Hemin Modified SnO2 Films on ITO‐PET with Enhanced Activity for Electrochemical Sensing

“…Therefore, various methods and electrodes have been used to try and overcome these issues and develop stable and sensitive hemin‐modified electrodes. These include adsorption on different carbon materials, incorporation in carbon paste, entrapment in a polymeric matrix, immobilization using dendrimers or cationic surfactants, mixing with metal oxide nanoparticles to create thin films and incorporation or drop‐casting on various nanocomposite materials .…”

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

“…2 ) partial double bonds, at room temperature. Similar to simpler 4-hydroxyphenyl-based amino- s -triazine analogues of 2a and 3 [ 35 – 36 ], the optimised ( a–a ) geometry was found to be largely dominant, both in the gas phase as well as in solution, e.g., DMSO, which was the most appropriate solvent for (VT) 1 H NMR and TEM investigations (see section 3.2).…”

“…1 and Scheme 4 (linker P-1 as piperazin-1-ium moiety) should be seen intuitively, a proton sponge-like comportment of G-1 piperazine dendron D-N<P>NH being not entirely ruled out [ 68 ]. In line with this hypothesis, we recently described [ 35 ] the aptitude of the non- O - n -octylated analogue of G-2 dendrimer 4 ( Scheme 3 ) to deprotonate Hemin completely (1:5 molar ratio), thus generating a new MOF for H 2 O 2 amperometric detection. More insights on this debate were obtained by means of DFT calculations only (see section 3.3).…”

“…Following up our contributions in the field of dendritic melamines’ synthesis, structural analysis [ 30 – 33 ] and electrochemistry [ 34 – 36 ], we recently become interested in the inclusion of 4-aminophenol, playing the role of peripheral unit, in G-0-2 dendritic melamines’ preparation, by applying the classic S N 2-Ar amination of cyanuric chloride in iterative-convergent strategies. Depending on several factors such as (i) the variable π-deficiency of the s -triazine branch-cells, (ii) basicity and conformational nature of the diaza-six-membered saturated heterocycle as linker and (iii) the global molecular shape, the resulted 4-aminophenol-based melamines displayed relevant redox properties [ 36 ] and, in some cases, selective aptitudes to produce MOFs (metal-organic frameworks) [ 35 ].…”

Detection Technologies for Reactive Oxygen Species: Fluorescence and Electrochemical Methods and Their Applications

“…As for biological molecules, they contain the redox agent heme, which acts as an active catalytic element for H 2 O 2 detection. Then, an electrochemical method measures an increased redox response (in the form of current or impedance change) due to the direct electron transfer (DET) between the active sites reacting with H 2 O 2 and the electrode surface [ 129 ]. However, the DET between the heme-containing biological molecules and the electrode surface is slow, which is likely due to the position of the redox-active centers deep inside the molecule structure and the protein shell on biological molecules [ 130 , 131 ].…”